The semiconductor integrated circuit (IC) industry has experienced exponential growth. Technological advances in IC design and material have produced generations of ICs where each generation has smaller and more complex circuits than previous generations. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometric size (i.e., the smallest component (or line) that can be fabricated) has decreased.
One type of capacitor is a metal-insulator-metal (MIM) capacitor, which is used in mixed signal devices and logic devices, such as embedded memories and radio frequency devices. Metal-insulator-metal capacitors are used to store a charge in a variety of semiconductor devices. A metal-insulator-metal capacitor is formed horizontally on a semiconductor wafer, with two metal plates sandwiching a dielectric layer parallel to the wafer surface.
An inductor is a passive electrical component that can store energy in a magnetic field created by an electric current passing through it. The inductor is used in integrated circuits for many different types of applications. These applications can include, for example, communication systems, radar systems, television systems, highpass filters and tank circuits. Inductors can be miniaturized for use in compact communication systems, such as cell phones and modems, by fabricating spiral inductors on the same substrate as the integrated circuit to which they are coupled using integrated circuit manufacturing techniques.
However, there are many challenges related to forming a via between an inductor and a metal-insulator-metal (MIM) capacitor.